Lawn-mower.



No. 851,075. PATBNTBDAPR. 2s, i907.-

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LAWNMOWBR.

` APPLIGATIN 'FILED MAY 18,-1905.

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No. 851,075. 4 PATENTED APR. 23,1907.

1 s; M. .Dosou LAWNl MOWERI` .gPPLIoATIoN FILED MAY 1s. 1905.

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snADRAcH MiLEsBoiasoN, or PORTLAND, MAINE.

LAWN-IVIOWER.

Specification of Letters'Patent.

Patented April 23, 1907.

Application filed May 18,1905. Serial No. 260.982.

To LZ/l 'wh/0771, t 711/007./ concern.-

Beit known that I, SHADRACH MILES DOB- soN, a citizen of the UnitedStates, residing at Portland, in the county of Cumberland and State ofMaine, have invented certain new and useful Improvements in Lawn-Mowers,of which the following is a specification."

The subject-matter of the present invention is an improvement in lawnmowers, the obj ect of which is to provide certain new and usefulconstructions in the driving mechanism and certain other improvements inthe structure and adjustment of the different parts, as will be morefully described hereina ter.

In the drawings in which like letters of reference indicatecorresponding parts throughout Figure 1, is a plan of the machine. Fig.2, is a section on the line 2-2 of Fig. l, Fig. 3, is a section on theline 3-3 of Fig. 1, Fig. 4,is a section on the line 4-4 of Fig. 1 Fig.5, is a section .on the line 5-5 of Fig. 1, and, Fig. 6, is a detail ofthe handle.

In referring to the drawings, the reference letter A represents thewheels of the lawn mower freely mounted on a stationary shaft S, andheld thereon by a washer and nut s. These wheels consist of an outer rimA2, which forms the tread and an inner rim A3, which has an internalgear and is connected to said outer rim by short webs or spokes. Theinner rim is in turn connected to and supported by the hub A1, throughspokes c.

B is a spider frame having a hub B1 firmly mounted upon the stationaryshaft S and bearing by spokes b a guard rim B2, which surrounds theinner rim A3 of the wheel A and protects the gear thereon from dirt orgrass.

C are a pair of counter-shafts arranged in alinement end to end, whichcarry pinions D on their outer ends, which pinions mesh with theinternal gear F on the inner rim A3, and are positively driven thereby.The shafts C have bearings near their outer ends in one of the legs ofthe spider frames B, which are thickened and bored for that purpose andfitted with ball bearings B3 screwed therein. The bore of this thickenedportion of the spider leg is/machined out on the wheel side to form acasing for the pinions D. G are ratchet wheels mounted on the inner endsof said shafts C and contained within the casing H, which forms a partof the cutter head and supplerts the cutter knives K centrally by earsThe casing His made in two parts, having a bearing in each part, as at7L, for the ends of the shafts just inside the ratchets, thus preservingthe alinement of the shafts while nermitting them to move independently.The casing is provided with pawls h1 pivotedly mounted therein in pairsto engage with the ratchet wheels on the ends of the two shafts C. Theratchets are arranged to engage the parts when4 the machine is drivenahead to actuate the cutters. The pawls 72.1 are pivoted at h2 and attheir opposite ends are enlarged and made heavier, as at h3. i

H1 are the end bearings of the cutter carriage, which support the endsof the blades and which are loosely mounted to freely revolve on theshafts C. The outer ends of these bearings H1 are coned to co-act to theball bearing B2, which takes up the end thrust of the cutter carriage aswell as forming the bearings for the shafts C.

N is the stationary cutter blade having an upwardly turned lip M1, saidblade being set in a deep groove o, in an L shaped arm O and removablyheld therein. The arm o is pivoted at g to an extension X of the spiderframe, and has oppositely acting adjusting screws P P1 for regulatingits position, which screws are in and against a portion of the samespider. i f

Q is the ga e roller mounted upon an adjustable arm Q1 and pivoted at gto the same extension of the spider as is the cutter arm O. Between theadjustable arm Q1 and the adjoining face of said extension, areoppositely faced notches cut radially about the pivot bolt g. Thesenotches on the two parts coact to hold the roller arm in its properadjustment when the j arts are tightened upon the bolt q. The rol er Qis bored at each end to receive the end of the arm Q1, which is in turnbored to receive the roller bearing q2 screwed into the end of theroller within said first mentioned bore. An oil cup S is mounted uponthe arm Q1 and connects with the bore above mentioned and supplieslubricant to this bearing without allowing dirt to gain access thereto.

T T1 is a clamp for uniting the shaft of the handle fawith its crossbarv. This clamp has a squared portion t1 for receiving the end of theshaft u and a cross tubular portion c1 for the crossbar c. Bolts t2passing outside of the bars hold the parts T T1 together, and a bolt t3,through the casing and shaft u hold the clamp firmly thereon. f

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The handle is connected by the usual fork to lugs on the inside of thespider frames B, being sprung onto the same, so that they are readilyremovable.

The operation of the machine is as follows, the various parts beingproperly adjusted in the manner indicated. As the machine is pushedforward the rotation of the wheels A impart through the internal gear Fand the pinions B a positive motion to the shafts C. When the cuttersare started the ratchets G engage the pawls g and turn the casing IIwhich carries with it the cutters. As long as the machine is drivenahead the pawls are held in engagement with the ratchets, but as soon aseither shaft is stopped or is retarded the pawls are released and therapid motion of the cutter casing causes them to be thrown out and thustend to remain, while the head is in rotation out of contact with theratchet wheels. If both of the driving wheels A are stopped, bothratchets stop, or if the wheels A are reversed, the ratchets also arereversed, but the cutters being freed from resistance, continue torotate rapidly and thus tend to throw off the pawls, as above describedand avoid the constant wear to which these parts are usually subjected.

Various modifications in the forms and the arrangements of the partshereinbefore specified, may obviously be made, without departing fromthe spirit of my invention.

What I therefore claim and desire to secure by Letters Patent, is

1. In a lawn mower, the combination with a pair of driving wheels of acounter-shaft having two parts independently driven thereby, a cuttercarriage mounted on said two part shaft and ratchet connections betweeneachof said parts of said shaft and said cutter carriage, substantiallyas and for the purpose specified.

2. In a lawn mower', the combination with a pair of driving wheels of acounter-shaft having two parts independently driven thereby, said partshaving on their adjacent ends ratchet mechanisms, a casing havinbearings for said adjacent ends and provide with independent ratchetmechanisms coacting with said first named mechanisms and cutter bladesoperatively connected with said casin 3. In aawn mower, a counter-shafthaving two independently driven portions with ratchets on their adjacentends, a casing for said ratchets provided with bearings for saidportions, said casing being provided with pawls adapted to co-act withsaid ratchets and cutter blades operatively connected with said casing.

4. In a lawn mower, a positively driven shaft having a ratchet, a cuttercarriage mounted thereon and having a pivoted pawl adapted to be thrownoutward by the rotation of said carriage when said ratchet is stopped.

5. In a lawn mower, a counter-shaft having two independently drivenportions with ratchets on their adjacent ends, a casing for saidratchets provided with bearings for the portions, said casing beingprovided with pivoted pawls adapted to be engaged by said ratchets intheir Iforward motion and to be thrown outward by the motion of thecasing when said ratchets are retarded, and cutters operativelyconnected with said casing.

6. In a lawn mower, a counter-shaft having two independently drivenportions with ratchets on their adjacent ends, a cutter head looselymounted on said shaft and comprising a casing for said ratchets havingbearings for said portions and said casing being provided with pivotedpawls adapted to be engaged by said ratchets in their forward motion andto be thrown outward as the ratchets are retarded, and cutters oeratively attached to said head substantia y as and for the purposespecified.

7. In a lawn mower, a positively driven shaft having a ratchet, a cuttercarriage mounted thereon and having a pivoted pawl, said pawl beingweighted at its free end whereby it will be moved centrifugally by therotation of said carriage when said ratchet is stopped.

8. In a lawn mower, a pair ofpositively driven shafts having ratchets, acutter carriage mounted thereon and having pivoted pawls, said pawlsbeing weighted at their free ends whereby they will be movedcentrifugally by the rotation of said carriage when said ratchets arestopped.

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In testimony whereof, I aiiX my signature in presence of two witnesses.

SHADRACH MILES DOBSON. Witnesses:

WILLIAM J. KNowLToN, MARION L. DUNBAR.

